The present disclosure relates to toners suitable for electrophotographic apparatuses.
Numerous processes are known for the preparation of toners, such as, for example, conventional processes wherein a resin is melt kneaded or extruded with a pigment, micronized and pulverized to provide toner particles. There are illustrated in U.S. Pat. Nos. 5,364,729 and 5,403,693, the disclosures of each of which are hereby incorporated by reference in their entirety, methods of preparing toner particles by blending together latexes with pigment particles. Also relevant are U.S. Pat. Nos. 4,996,127, 4,797,339 and 4,983,488, the disclosures of each of which are hereby incorporated by reference in their entirety.
Toner systems normally fall into two classes: two component systems, in which the developer material includes magnetic carrier granules having toner particles adhering triboelectrically thereto; and single component systems (SCD), which typically use only toner. Placing charge on the particles, to enable movement and development of images via electric fields, is most often accomplished with triboelectricity. Triboelectric charging may occur either by mixing the toner with larger carrier beads in a two component development system or by rubbing the toner between a blade and donor roll in a single component system. Toners should also display acceptable triboelectric properties, which may vary with the type of carrier or developer composition.
Polyester toners have been prepared utilizing amorphous and crystalline polyester resins. An issue which may arise with this formulation is that plasticization may occur upon combining the amorphous and crystalline resins, which may result in a decrease in the glass transition temperature of the toner. The resulting toner may thus have a glass transition temperature equal to or less than the temperature found in an electrophotographic machine/apparatus, which may give rise to image defects.
Improved toners, and methods for forming such toners, thus remain desirable.